1. Field of the Invention
The present invention generally relates to an optical disk recording method, an information processing method, an optical disk device, an information processing device, and a controller usable in the optical disk device.
2. Description of the Related Art
In recent years, as an optical disk device recording information on an optical disk such as a CD-R is becoming more widely used as an exterior recording device of a personal computer, the demand for higher-speed recording is becoming very large.
The rotational speed of the optical disk increases when performing high-speed recording onto the optical disk. When the machine accuracy of the optical disk is poor, a problem such as track deviation wherein an optical spot recording information onto the optical disk deviates from a track due to side-runout and decentering is likely to occur. When the track deviation occurs during recording, the optical disk becomes useless and this imposes a critical problem.
For an optical disk such as a compact disk, a representative of which is a CD-R, density of recording data is identical in all surface areas of the optical disk. When linear velocity of the optical disk (tangential velocity at the location of the optical spot on the optical disk) performing recording/reading data on the optical disk is constant in the range of 1.2–1.4 m/s, channel bit rate of the data is 4.3218 Mbit/sec. Recording velocity under this condition is so-called equi-velocity or 1x velocity. A method of controlling the rotation of the optical disk so as to keep the linear velocity constant is called a Constant Linear Velocity (CLV) method. The optical disks such as the CDs adopt a format wherein the linear velocity is to be kept constant as mentioned above, thus CLV recording (recording using the CLV method) is performed. The recording is performed with a velocity Qf an integral multiple of reference 1x linear velocity (such as 1x, 2x, 4x, 8x, 12x, 16x, 20x, etc., where x is a scale factor).
When performing the CLV recording, the number of revolutions per minute at an inner periphery of the optical disk and at an outer periphery of the optical disk varies greatly. Needless to say, for the CLV method, the number of revolutions per minute while recording at the inner periphery of the optical disk is larger than the number of revolutions per minute while recording at the outer periphery of the optical disk. In order to prevent track deviation from occurring during recording, it is necessary to determine CLV (constant linear velocity used in the CLV method) so that track deviation will not occur at the innermost periphery of the optical disk where it rotates at maximum speed. Then, in this case, the number of revolutions per minute at the outer periphery of the optical disk has a margin for the track deviation, that is, the rotational speed is reduced.
There has been proposed so-called ZCLV (Zone CLV) method wherein the track of the optical disk is divided into a plurality of zones, such as an inner periphery, an intermediate periphery, and an outer periphery and the CLV of each zone is determined so that continuous recording is possible. This method realizes high-speed recording. FIG. 1 shows an example realizing ZCLV recording (recording using the ZCLV method). In FIG. 1, the horizontal axis represents a location (time) on the optical disk and the vertical axis represents recording velocity. In this example, the optical disk is divided into 3 zones (Lead-In to t1, t1 to t2, and t2 to Lead-Out) and the CLV of each zone is determined as s1, s2, and s3, respectively. At transition (t1, t2) of the zones, the continuity of the data is maintained by making use of the technique described in Japanese Laid-Open Patent Application No. 10-49990.
In Japanese Laid-Open Patent Application No. 7-93873, a ZCLV recording method for an optical disk already having divided zones is described. However, with this method, recording onto an optical disk comprising only a single spiral track, such as a CD-R disk, is not possible since divided zones are not provided.
Japanese Laid-Open Patent Application No. 11-66726 describes, as in JPA No. 7-93873, a ZCLV recording method for an optical disk already having divided zones. However, again with this method, recording onto an optical disk comprising only a single spiral track, such as a CD-R disk, is not possible since divided zones are not provided.
There has been also proposed an optical disk device that performs ZCLV recording by performing interruption and resumption of recording at any location on the optical disk, ensuring the continuity of the data, and increasing the CLV when resuming the recording.
Further, there have been proposed a method of determining zones for optimum recording for any type of optical disk, a method of determining recording velocity for each zone, and a method of determining recording power. These are all to describe specifically the method of performing ZCLV recording onto an optical disk.
In the above-mentioned ZCLV recording methods, parameters determined by several predetermined ZCLV recording modes are retrieved and correspondence is made between such parameters and each type of the optical disk. However, since it is not possible to set a flexible relation between velocity and time, there arises a phenomenon such as even in a case of an optical disk having a potential of recording at 20x velocity in one area, the recording velocity may be increased only up to 16x velocity when the area close to the outer periphery can only be recorded at 16x velocity.
For example, an optical disk may have a relation between recording area (recording time) and servo signal fluctuation as shown in FIG. 2, with the servo signal fluctuation increasing toward the outer periphery of the optical disk. In this example, even though the servo signal fluctuation at the intermediate periphery of the optical disk is less, the ZCLV recording mode is determined by taking into consideration the outer periphery of the optical disk where the servo signal fluctuation is large. Therefore, the maximum capable velocity of 20x may not be utilized. Thus, since the maximum recording velocity is determined adaptively for the area where the servo signal fluctuation is large, the potential of the optical disk is not fully taken advantage of.
Also in a case where the optical disk device itself determines the optimum recording velocity, the recording onto the optical disk may be performed with a velocity that is different from that determined by a user using writer software. When the optimum recording velocity is lower than that determined by the user, the recording operation will not end when the expected recording completion time is reached, thus it may lead to a problem in the optical disk device, or it may be mistaken that a personal computer running the writer software to perform recording is hung-up, etc.
Further, when the optimum recording velocity differs from that selected by the user, the expected recording completion time is unclear.
Also, the optical disk device may not allow the user to determine the recording velocity by her/himself by performing several trial recordings. For example, even when the user possesses a number of identical optical disks, the user cannot obtain a limit of recording velocity of such optical disks by carrying out some trial recordings by her/himself.